{"id":107121,"date":"2026-04-17T12:49:17","date_gmt":"2026-04-17T10:49:17","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&p=107121"},"modified":"2026-10-13T11:14:48","modified_gmt":"2026-10-13T09:14:48","slug":"televue-ethos-17mm-100-degree-eyepiece","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/televue-ethos-17mm-100-2-oculair\/","title":{"rendered":"TeleVue Ethos 17mm \u2013 100\u00b0 2\u2033 Eyepiece"},"content":{"rendered":"

TeleVue Ethos 17mm : 100\u00b0 2\u2033 Eyepiece: Ethos eyepiece with 100-degree field of view<\/strong><\/h2>\n\n\n\n

The Ethos 17 mm opens the series of 17, 10, and 6 mm and is the lowest magnification model that can still handle moderate light pollution. With a field stop of 29.6 mm, the true field of view is close to that of a 26 mm Nagler, but at a higher magnification.<\/p>\n\n\n\n

This is a 2-inch eyepiece. A focuser or star diagonal with a 2-inch connection is therefore required.<\/p>\n\n\n\n

\"TeleVue<\/figure><\/figure>\n\n\n\n

What a 100-degree field of view does<\/h4>\n\n\n\n

A classic Ploessl has 50 degrees, a Nagler has 82 degrees. At 100 degrees, your eye can no longer take in the field at once: you\u2019re looking around the image instead of *at* it. That\u2019s the effect the Ethos series is known for.<\/p>\n\n\n\n

Practically, this also means that objects remain in view for longer. On a manually tracked Dobson, this saves constant readjustment.<\/p>\n\n\n\n

Overview with a dark background<\/h4>\n\n\n\n

At low magnification, the sky background becomes lighter, especially under an urban sky. Because the Ethos achieves the same true field of view at a higher magnification, the background remains darker and faint nebular structure stands out better.<\/p>\n\n\n\n

For extended objects like the North America Nebula or the Pleiades, this is the model that combines overview and contrast.<\/p>\n\n\n\n

Viewing Comfort and Dioptrx<\/h4>\n\n\n\n

The eye relief is 15 mm at every focal length in the series. The height of the foldable eyecup is adjustable, so your eye is always in the same position.<\/p>\n\n\n\n

If you wear glasses due to astigmatism, you can replace them with Dioptrx on the eyepiece. This corrects your own cylindrical aberration without the eyeglass lenses costing contrast and eye distance.<\/p>\n\n\n\n

In your telescope<\/h4>\n\n\n\n

In a telescope with a brand point spread function of 1,200 mm, this eyepiece provides approximately 71x magnification with a true field of view of about 1.41 degrees. You can calculate this for your own telescope using the field stop: true field of view = 57.3 \u00d7 field stop divided by the telescope\u2019s brand focal length.<\/p>\n\n\n\n

The field stop on this model is 29.6 mm. That number\u2014and not just the brand point spacing\u2014determines how much of the sky you actually see.<\/p>\n\n\n\n

Included<\/h3>\n\n\n\n